I'm torn between 2 nursing dx and I need help please...:)))

Thank you in advance if you do respond...ok...so my pt has COPD, CHF w/pleural effusion (RLL infiltrates on CXR). placed on a ventilator 3 weeks ago r/t severe destating. He has copious, thin secretions that have to be suctioned regularly and he gags and destats...which subsides after suctioning. RLL crackles, with mild Rhonchi on expiration. ABGs reveal hypoxemia, respiratory and metabolic acidosis, Labs...low H & H, Low K+, and Low RBC's, He is anuric r/t ESRD. Now normally my experience in the past with dialysis patients they are fluid volume overload...and also the fact that he has ESRD and CHF...Here's the thing...He had Dialysis 15 hours prior to my shift so he was not FVO. My question is...my care plan books according to my s/s keep leading me to Impaired Gas Exchange...I get that...because of the ABG's...but my mind keep saying...if he cant get the air in...isnt that the TOP priority??? Can someone just tell me their take on it? His s/s fit in both Impaired Gas Exchange and Ineffective airway clearance....I need the Major Priority...and I'm leaning towards Ineffective Airway Clearance...and Decreased Cardiac Output...or Ineffective Cardio-pulmonary tissue perfussion...(this will cover the gas exchange issues and sepsis issue)...
He was septic for 2 weeks. (most likely from him being on immunosuppresants-post liver transplant 10 years) but now taken off the levophed...WBC's good..A febrile, still tachycardic, hypotensive and has diarrhea. It's my own fault and I shouldve asked...but.... if he's taken off the levophed...and his WBCs have returned to normal limits...Is he no longer have sepsis? I'm not asking for anyone to "write my care plan"...I'm just in need of some guidance...Thank you for taking the time to read this...

Impaired gas exchange is priority, then ineffective airway clearance as he is not processing what air he does get in effectively, AEB decreased RBCs and messed up ABGs. Think of it this way...even if he was able to get air in there, what would his body do with it?